North Ray crater is a small crater in the

Descartes Highlands The Descartes Highlands is an area of lunar highlands located on the near side that served as the landing site of the American Apollo 16 mission in early 1972. The Descartes Highlands is located in the area surrounding Descartes crater, after whi ...

of the Moon visited by the astronauts of

Apollo 16 Apollo 16 (April 1627, 1972) was the tenth crewed mission in the United States Apollo space program, administered by NASA, and the fifth and penultimate to land on the Moon. It was the second of Apollo's " J missions", with an extended sta ...

. The name of the crater was formally adopted by the

IAU The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...

in 1973. It is the largest crater sampled by astronauts during the Apollo program. The Apollo 16

Lunar Module The Apollo Lunar Module (LM ), originally designated the Lunar Excursion Module (LEM), was the lunar lander spacecraft that was flown between lunar orbit and the Moon's surface during the United States' Apollo program. It was the first crewed ...

(LM) ''Orion'' landed between North Ray and South Ray craters on April 21, 1972. The astronauts

John Young John Young may refer to: Academics * John Young (professor of Greek) (died 1820), Scottish professor of Greek at the University of Glasgow * John C. Young (college president) (1803–1857), American educator, pastor, and president of Centre Coll ...

and

Charles Duke Charles Moss Duke Jr. (born October 3, 1935) is an American former astronaut, United States Air Force (USAF) officer and test pilot. As Lunar Module pilot of Apollo 16 in 1972, he became the tenth and youngest person to walk on the Moon, at ...

explored the area between the craters over the course of three EVAs using a

Lunar Roving Vehicle The Lunar Roving Vehicle (LRV) is a battery-powered four-wheeled rover used on the Moon in the last three missions of the American Apollo program ( 15, 16, and 17) during 1971 and 1972. It is popularly called the Moon buggy, a play on the t ...

, or rover. They visited North Ray on EVA 3, at station 11, about 4.4 km north of the landing site. On the way, they drove along the rim of the similar sized but older crater Palmetto, which is approximately 3 km south of North Ray. North Ray crater is approximately 1 km in diameter and approximately 240 m deep. The astronauts observed that the upper 50 m of the slope is gentle, but that it becomes steep below 50 m, and they could not observe the bottom. The inner slopes are covered by boulders up to 5 m across. A huge (10 m high x 20 m long) boulder, known as House Rock, lies near the southeastern rim. A smaller boulder that is almost certainly a fragment of House Rock is officially known as South Boulder, but unofficially known as Outhouse Rock.Apollo 16 Preliminary Science Report
(NASA SP-315), 1972 The

ray system A ray system comprises radial streaks of fine '' ejecta'' thrown out during the formation of an impact crater, looking somewhat like many thin spokes coming from the hub of a wheel. The rays may extend for lengths up to several times the diameter ...

, which can be seen from orbit, was not obvious on the ground. North Ray cuts into the Cayley Formation of

Imbrian The Imbrian is a lunar geologic period divided into two epochs, the Early and Late. Early Imbrian In the lunar geologic timescale, the Early Imbrian epoch occurred from 3,850 million years ago to about 3,800 million years ago. It overlaps the en ...

age, but the crater itself is much younger, of Copernican age, based on the presence of rays. (See also section on age below.) Apollo 16 PSR Figure 6-65 Planimetric map of Station 11

Apollo 16 PSR Figure 6-65 Planimetric map of Station 11

Gallery

A16PSR Figure 6-61 Geologic map of North Ray crater.jpg, Geologic map of North Ray crater Image:North Ray crater AS14-69-9535.jpg, Oblique

Apollo 14 Apollo 14 (January 31, 1971February 9, 1971) was the eighth crewed mission in the United States Apollo program, the third to land on the Moon, and the first to land in the lunar highlands. It was the last of the " H missions", landings at s ...

image, facing east File:AS16-105-17174 (21056362103).jpg, Telephoto image of rocks in the interior walls of the crater AS16-106-17340 (21709978761).jpg, John Young using the rake tool to collect a sample (67700) at the southeast rim, with the rover at the central horizon, and white breccia boulders at the right horizon File:A16PSR Figure 6-59 white breccia boulders.jpg, White breccia boulder along the south rim of the crater, showing typical dark-clast population, rounded, unjointed surfaces, and well-developed fillet File:House Rock AS16-106-17336HR.jpg, House rock as viewed from the white breccia boulders (looking northeast) File:House Rock AS16-106-17341-17344.jpg, East side of House Rock

Age

Based on sample 67955, a noritic

anorthosite Anorthosite () is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most c ...

collected from Outhouse Rock, the impact that created North Ray crater was about 50 million year ago. This is based on the measured duration of the rock's exposure to

cosmic rays Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...

. The rock itself is dated at 4.20 ± 0.07 b.y. by Sm/Nd radiometric dating.

Samples

The following samples were collected from North Ray Crater (Station 11), as listed in Table 6-II of the Apollo 16 Preliminary Science Report, which does not include samples smaller than 25 g weight (of which there were many). Sample type, lithology, and descriptions are from the Lunar Sample Atlas of the Lunar and Planetary Institute.Lunar Sample Atlas
Lunar and Planetary Institute

External links

Geology of North Ray Crater
Section D2 of Geological Survey Professional Paper 1048, by George E. Ulrich. 1981.
Apollo 16 Traverses
78D2S2(25),

Lunar and Planetary Institute The Lunar and Planetary Institute (LPI) is a scientific research institute dedicated to study of the Solar System, its formation, evolution, and current state. The Institute is part of the Universities Space Research Association (USRA) and is supp ...

References

{{reflist Apollo 16 Impact craters on the Moon